Paper making machines



P 1959 M. J. BERLYN 2,903,061

PAPER MAKING MACHINES Filed July 2', 1956 6 Sheets-Sheet 1 iii an a J INVENTOR fit I 6501 yu Sept.'8, 1959 M..J. BERLYN 2,903,061

PAPER MAKING MACHINES Filed July 2, 1956 1 s Sheets-Sheet 2 INVENTOR Rita/ my;

Sept. 8, 1959 M. J. BERLYN 2,903,061

' PAPER MAKING MACHINES Filed July 2, 1956 y i s Sheets-Sheet s l-N VENTOR )2 I BmLyu" Sept. 8, 1959 M. J. BERLYN 2,903,061

v PAPER MAKING MACHINES Filed July 2, 1956 6 Sheets-Sheet 5 INVENTOR M. I finely/v Sept. 8, 1959 M. J. BERLYN Y 2,903,051

' PAPER MAKING MACHINES Filed July 2, 1956 r 6 Sheets-Sheet 6 nvveuron M. I Emlyu United States Patent PAPER MAKING MACHINES Martin J. Berlyn, Montreal, Quebec, Canada, assignor to Domimon Engineering Works Limited, Montreal, Quebec, Canada Application July 2, 1956, Serial No. 595,223

Claims. (Cl. 162-295) because this speed is a factor in keeping to a minimum the cost of machines, and machine-room buildings, per unit weight of paper produced per unit of time.

. With the same object, such machines are usually constructed to make the widest possible sheet consistent with the structural and mechanical limitations imposed by speed of operation.

In the conventional Fourdrinier paper machine an aqueous suspension of fibre is flowed through a slice onto a moving endless taut wire screen, commonly referred to as the forming wire.

Some 98% of the original water isremoved by th time the web leaves the wine.

. Various devices such as flat suction boxes, table rolls and suction rolls are employed in conjunction withthe .wire in order to speed up the drainage.

Some of these devices impart frictional drag on the wire. This friction not only calls for considerable power to drive the wire but results in short wire life; about six days in the case of a modern high-speed newsprintpaper machine. The wear of the wire is also accelerated by the presence in thestock of abrasive particles from the grindstones used in preparation of groundwood stock. These abrasive particles become embedded in the tops of suction boxes and attrition of the wire as it scrapes over these gritty surfaces, with normal loading augmented by suction, is inevitable. i

To a certain extent the drainage of water through the wire is a function of time; this means-that, for speeds substantially higher than those used at present, the wire would, using contemporary basic design, have to be longer than for present speeds, and even now wire lengths in the neighborhood of 130 feet are not uncommon.

In present-day newsprint paper machines, with their long taut Fourdrinier wires, a wire-change takes about 'two hours; more or less, varying with the detail design of the machine. This means down-time of around 100 hours per year, and may represent the loss of 1200 tons production of paper per year per machine.

If contemporary basic design is adhered to, substantial increase of lineal speed can oly be achieved by making the machine longer, to satisfy the time requirement of the draining function, and by increasing the roll diameters or decreasing'the roll lengths (and, consequently,

the sheet width) in order to remain within the limitations of the roll dynamics,

ice

This is to say that, if contemporary basic design is not to be abandoned there is now little apparent scope for substantial improvement of efliciency in terms of the weight of paper produced per unit of time per unit of first cost.

The critical whirling speeds of rolls vary inversely as the square of their length. It is apparent therefore that dynamic limitations to high speed decrease more rapidly than decrease of roll length.

A narrow-sheet paper machine operated just short of the threshold of roll whirling would therefore be capable of producing a greater weight of paper per unit of width per unit of time than a wider machine.

If, owing to the higher speed of this narrower machine, it must be made proportionately longer to satisfy the draining time requirement then little or nothing would be gained in weight of paper produced per unit of time per unit of first cost.

The present invention provides an open-side Fourdrinier section in which narrow high-speed construction is combined with means for drastically reducing the draining time, thereby avoiding the necessity for increased machine length at this higher speed.

An object of the invention is to provide improved means for extracting water from an aqueous suspension of fibres.

Another object is to provide a Fourdrinier machine which, in respect of its physical size, will have substantially increased output as compared with contemporary practice.

Another object is to exploit fully the potential for mechanical and structural simplification in a narrow Fourdrinier machine.

Another object is to provide means for easy and rapid changing of the wire of a F ourdrinier machine.

Another object is to provide a Fourdrinier machine of substantially reduced cost.

Another object is to provide a Fourdrinier machine requiring substantially reduced power input.

Another object is to provide a Fourdrinier machine with improved wire life.

Another object is to provide a Fourdrinier machine with improved wire-guiding characteristics.

Another object is to provide a Fourdrinier machine executed so as to require the minimum number of different kinds of component parts.

Another object is to provide a Fourdrinier machine which is not noisy in operation.

Proceeding now to a more detailed description of the invention, reference will be had to the accompanying drawings, in which:

Fig. l is a schematic representation of a Fourdrinier section designed in accordance with my invention.

Fig. 2 is an elevational view illustrating a cantilevered mounting of the breast roll and the underlying wire guide roll schematically shown at the left-hand end of Fig. 1. In this figure, the rolls are shown mounted on a vertical frame structure at one side of the Fourdrinier section and as they appear when viewed from the couch end of the Fourdrinier section.

Fig. 3 is an elevational view showing the assembly of Fig. 2 as it appears when looking axially towards the outboard ends of the breast roll and the underlying wire guide roll.

Fig. 4 is an elevational view illustrating a cantilevered mounting of the couch roll and underlying slack-adjusting roll schematically shown at the right hand end of Fig. 1. This figure shows the couch roll, the slack-adjusting roll and their supporting frame structure as these elements appear when viewed from the couch end of the Fourdrinier section. I

Fig. 5 is an elevational view of the assembly of Fig. 4

as it appears when looking toward the outboard ends of the couch roll and slack-adjusting roll.

Fig. 6 is a vertical sectional view of the roll assembly shown in Fig. 2, the section being taken substantially along the section line 6-6 of Fig. 7.

Fig. 7 is a horizontal section taken substantially along the section line 7--7 of Fig. 6.

Fig. 8 is an enlarged view of'a portion of the assembly shown in Fig. 7. As shown in these drawings, an endless, slack, Fourfdrinier wire (Fig. 1) is trained around a series of hori- 'zontal rolls including a breast roll 6, acouch roll 7, and wire return rolls 8 and 9. p The breast roll 6 is power driven and serves to impart high speed travelling movement to wire 5 in the direction "indicated by arrow A in Fig. l. The driving means for breast roll 6 is represented in Figs. 2, 6 and 8 by a motor driven shaft indicated at 10 and a drive motor indicated at 100: in Figure 6. The couch roll 7 and wire return rolls 8 and are'mounted for free rotation and are m tated solely by contact with the travelling wire 5.

In the embodiment selected for illustration, the couch 'roll 7 is located at a higher elevation than the breast roll 6 and the upper run of wire 5 travelling from the breast roll to the couch roll is in a free catenary C between these rolls and is free of contact with supporting and friction surfaces such, for example, as the table rolls and suction -boxesemployed in conventional Fourdrinier machines.

The aqueous suspension of pulp fibres to be'formed into a sheet is fed onto the concavely curved upper side of the catenary portion of the wire at the breast roll 6 :and the formed Wet sheet is removed, preferably in a vertical or substantially vertical direction, from the catenary portion of the wire at the couch roll 7. I In order to obtain the best results, the pulp suspension "should be fed onto the breast roll end of the catenary .portion of the wire under pressure'at a suitably selected velocity and in a downward direction tangential or approximately tangential to the breast roll.

While various types of head boxes and slices may be used for feeding the pulp suspension onto the wire in the prescribed manner, the optimum conditions for high speed formation of the pulp suspension into a satisfactory sheet are realized when the head box and slice assembly used is of the type described and claimed in my co-pending application Serial No. 595,l42,'filed July 2, 1956. This particular type of head box and slice assembly is schematically shown in Fig. l as comprising a substantially cylindrical head box 11 from which the pulp suspension is discharged downwardly through a tangential slice outlet 12 onto the breast roll end of the catenary portion of the wire. An important characteristic of this type of head box is that the pressure is raised within the cylinder 11 by whirling the stock about the axis of the cylinder. As set forth in my aforesaid co-pending application this Whirling of the stock about the axis of the cylinder is achieved by the provision of an impeller rotating within the cylinder and having approximately the same axial length as the inside length of the cylinder. The head box 11 may be and preferably is trunnion mounted to provide for easy adjustment of the position of the slice outlet 12 in relation to the wire and the breast roll to best suit different operating conditions. The removal of the wet and relatively Weak formed sheet S from the couch roll end of the catenary portion of the Wire may be achieved through the agency of a water shower 13, an air slice 14, and centrifugal rejection of the sheet by the rapidly rotating couch roll 7.

The water shower 13 is located below the upper run of the wire ahead of the couch roll 7. The water delivered through this water shower wets the underside of the wire and softens the sheet fibres wrapped around individual strands of the woven wire and thus conditions the wet sheet for lifting off the upper surface of the wire without tearing.

The air slice 14 is arranged so that the blast of air delivered therethrough is directed'into the convergent space 15 between the surface of the couch roll 7 and the adjacent upwardly travelling portion of the wire. This blast of air exerts on the underside of the formed sheet a pressure sufficient to just float the sheets on the surface of the mesh of the wire. The high speed of rotation of the couch roll 7 gives rise to acentrifugal effect at its surface powerful enough to reject the formed sheet S from the Wire 5 at a tangent to thesurface of thefcou'ch rollwhere the wire wraps on to said surface.

It is desirable that the formed sheet S, which is wet and relatively weak, be directed in a vertical or substantially vertical direction from the forming'wire 5 in order to imposethe minimum stress on the structure of the sheet and give maximum immunity from wet end breaks. In the embodiment of the invention shown in Fig. 1, this is provided for by the arrangement of the couch roll and the catenary portion of the Wire, the high speed of rotation of the couch roll and the assistance given by the water shower. 13 and air slice 14.

The removal of the wet sheet S in a vertical onsubstantially vertical direction from the couch roll end of the forming wire 5 makes it feasible to pass the wet sheet directly through a suitably located press section without the aid of .a pick-up roll or press felt and this, in turn, makes it possible to substantially increase the water extracting efficiency and operating speed of .the press section. In. order to illustrate this I have shown schematically in Fig. 1 a press section 17 through which the wet sheet is passed vertically from; the couch end of the formfrom the forming wire toand through the 'first press section.

As here shown, the press section 17 includes two relatively slender or small.diameter high-speed press'rolls 18 and 19 affording a press'nip through which the wet sheet S is passed vertically from the couch roll end of the forming wire. Each of these. small diameter press rolls is backed up by two backing up rolls '20 and 21 of larger diameter. It will thus be seen that each of the press rolls 18 and 19 has three bearing. points which enable it to be run at very high operating speeds without whip or whirling. Torque can be'applied to the press rolls 18 and 19 without vibration by employing a press roll drive including worm'speed increasing gears directly driving said press rolls. The small diameter of the press rolls brings the roll centres close to each other and this imposes a low limit on the diameter of driving gears mounted on the roll shafts but, by employing the worm and wormwheel type of speed-increasing gear train, in which the small-diameter worms are mounted on the roll shafts, adequate power capacity of the roll drive may be provided despite the inherently short distance between roll centres.

The high speed of rotation of the press rolls 18 and 19 givesrise to centrifugal effects at the roll surfaces which ensure that the sheetS will leave the press nip cleanly with sticking'toor wrapping itself around either of the press rolls.

A basic and important novel feature of the invention described herein is the movement of the upper suspensioncarrying run of the Fourdrinier wire through a suitably .curved path of travel from the press roll to the couch roll feasible. Put in another way, the reduction of. drainage time afforded by this invention makes it possible to. in-

crease.the'operationspeed while decreasing the length e as:

of the Fourdrinier wire and this is directly contrary to current practice.

The great increase in the running speed of a Fourdrinier wire which is made possible by the drastically reduced drainage time aiforded by this invention can also be taken advantage of to narrow the width of a Fourdrinier machine without such loss of output capacity as this would entail in the case of conventional machines. At 100 feet per second a 66-inch width newsprint machine could produce approximately 250 tons of newsprint per 24 hours and it is obvious that, if such a machine could be made appreciably shorter in overall length than present newsprint machines, attractive economies in cost of machines and buildings would be realized. The provision of such a narrow width, high-speed, high-output machine is feasible if the Fourdrinier section is designed in accordance with the principles of this invention to effect rapid centrifuging of the water from the wire-carried pulp suspension during travel thereof from the breast roll to the couch roll.

In the case of the proposed high-speed narrow width Fourdrinier machine such, for example as a 66-inch width machine, the permissible reduction in the lengths of the breast roll 6, couch roll 7 and wire return rolls 8 and 9 makes is feasible to provide an open-side Fourdrinier section by cantilevering the said rolls in the manner illustrated in Figs. 2 to 7 inclusive. As here shown, each of the rolls is supported, on the cantilever principle, from a frame structure 23 at one side of the Fourdrinier section so that the end of each roll remote from the frame structure is free. The open-side Fourdrinier design, the elimination of the conventional table rolls and suction boxes, and the slack' condition and narrow width of the Fourdrinier wire enable wires changes to be eifected with much greater ease and rapidity than has heretofore been possible.

In addition to facilitating wire changes the elimination of the conventional table rolls and suction boxes, as contemplated by the present invention, increases the useful life of the wire by reducing the frictional drag and Wear thereon and also reduces the power required to drive the wire.

Another advantage of the invention is that, in the embodiment shown in the drawing, the design of the Fourdrinier section is simplified and made more economical by the cantilever mounting of the wire rolls and by the fact that only four wire rolls are employed for moving and guiding the wire through its prescribed path of travel.

The breast roll 6 and couch roll 7 are adjustably mounted so that the alignment thereof may be accurately adjusted.

The wire return rolls 8 and 9 are mounted for appropriate adjustment to enable roll 8 tobe used as a trimming roll or wire guide for keeping the wire in the prescribed path of travel and to enable the roll 9 to to be used as a slack-adjusting roll for regulating the length of wire in the catenary C.

The construction and assembly of the component parts of the rolls 6, 7, 8 and 9 and the adjustable mounting of these rolls on their respective frame structures 23 will now be described in detail with reference to Figs. 2 to 7 inclusive.

The frame structure 23 supporting breast roll 6 and guide roll 8 rises from a suitable supporting base 25 at the side (the driving side) remote from the tending side of the machine and is provided with counterbored bosses 26 and 27 (Figs. 6 and 8) into which are fitted hollow open-ended cantilever structures 28 and 29 respectively. Cantilever structures 28 and 29 are attached to frame 23 by bolts 30. Each of the cantilever structures 28 and 29 is provided with a bearing seat 31 at its end remote from frame 23. Each bearing seat 31 carries a self-aligning bearing 32.

Journalled in bearings 32 of cantilever structures 28 and 29 are shafts 33 and 34 respectively.

Breast roll shaft 33 is fitted into bore 35 of boss 36 in diaphragm 37 of the breast roll shell 38 which is driven by shaft 33 through key 39. Shaft 33 is maintained coaxial with breast roll shell 38 at the end remote from frame 23 by means of cover plate 40 which fits into oounterbore 41 of breast roll shell 38.

Shaft 34 carries the roll shell 43 of the lower guide roll 8. Shaft 34 is journalled in the tending side end of cantilever structure 29 and is maintained co-axial with the guide roll shell 43 by internal arrangements identical with those previously described in connection with the breast roll assembly.

Towards its drive side end, breast roll shaft 33 has a bearing seat 45 carrying a self-aligning bearing 46 which is carried in a two-piece bearing housing 47. The drive side end of cantilever structure 28 is provided with a counterbore 49 in which is located clamping ring 50. Clamping ring 50 is provided with a shoulder 51 adapted to retain split rings 52 in undercut groove 53 in counterbore 49 of cantilever structure 28. Clamping ring 50 is provided with clamping bolts 54 which are adapted to maintain two-piece bearing housing 47 in heavy frictional contact with face 55 of cantilever structure 28. It is to be noted that the outside diameter of two-piece bearing housing 47 is less than the diameter of counterbore 49 of cantilever structure 28; this provides for radial displacement of the drive side end of shaft 33 when clamping bolts 54 are backed off.

Three equally spaced radial set screws 56 are threaded through the wall of cantilever structure 28 in the plane of two-piece bearing housing 47 and by means of these setscrews 56 the alignment of roll 6 may be accurately adjusted. When made, this adjustment maybe locked by means of clamping bolts 54 and setscrews 56 may be withdrawn to prevent tampering.

The extreme drive side end of shaft 33 carries a flexible coupling 57. Beyond coupling 57 is floating shaft 58 which' is driven from motor shaft 10 through flexible coupling 59.

The driving motor and its mounting are not shown.

At the drive side end of guide roll shaft 34 a bearing seat 61 (Fig. 8) carries self-aligning bearing 62 which is held in two-piece bearing housing 63 which is keyed to rockshaft 64 by taper pin 65. At each end of rockshaft 64 there is a bearing seat 66 (Fig. 7) onto which is fitted a bearing 67 which is carried in a one-piece bearing housing 68 having an intergral flange 69 by means of which it is bolted to frame 23.

Two-piece bearing housing 63 has integrally formed on it servo lever 71 and restoring-mechanism lever 72". Servo lever 71 is swung in one direction by servo piston 73, which slides in servo cylinder 74, and is swung in the other direction by return spring 75 which works in spring guide cup 76. Cylinder 74 is mounted in the frame base 25 directly opposite spring guide cup 76 which slides in a spring pocket 77 housing the spring 75.

Servo cylinder 74 is closed by a combined hollow cover and valve casing 78 in which is slidingly housed a spool-type reciprocating pilot valve 79. b

Valve casing 78 is provided with a port 80 placing the interior thereof in communication with cylinder 74. Valve casing 78 is also provided with an inlet port 81 through which servo fluid is supplied under pressure to the interior of the valve casing and with an exhaust port 82 through which the interior of the valve casing is connected to drain. The routing of pressure fluid to and from cylinder 74 via the valve casing ports here referred to is controlled by movement of valve 79 as hereinafter,

explained.

A valve actuator 84 has a plunger 85 on the end 85:: of which the intermediate portion of a rocker 86 is pivoted by means of a pivot pin 86". One end ofrocker 86 is connected to restoringrnechanism lever 72 by 7 87 and the other end of rocker 86' is connected to pilot valve 79 by link 88.

Wire guide roll 8 may be canted slightly out of parallel with breast roll 6 in a vertical plane due to horizontal movement of the lower end of servo lever 71 either by servo piston 73 or by return spring 75. Two-piece bear ing housing 63 and servo lever 71, rocking about the axis of rockshaft 64 constitute a bell-crank for imparting vertical displacements to the drive side end of shaft 34 through the medium of self-aligning bearing 62 As in the case of breast roll 6, wire-guide roll 8 is provided with a self-aligning main bearing (not shown in Fig. 8 but corresponding to the bearing 32 shown in Fig. 6) which accommodates the canting imparted by the movements of servo lever 71.

In combination with servo lever 71, restoring-mechanism lever 72 constitutes a bell crank also. If actuator plunger 85 moves downwards pilot valve 79 is displaced downwards and pressure fluid flows from inlet port 81 to servo cylinder 74, and forces servo piston 73 in a direction overcoming the opposing force of return spring 75 and turning two-piece bearing housing 63, with its integral levers 71 and 72, clockwise about the axis of rockshaft 64. Through link 87 therefore, rocker 86 is turned counter-clockwise and this, through link 88, raises pilot valve and cuts off further supply of pressure fluid to servo cylinder 74. By this means, hunting instability of the wire guiding function is prevented.

Actuator 84 may be mechanical, electric, hydraulic or pneumatic or any combination of these. It responds to signals from a sensor which detects lateral movements of the wire. The movement of actuator plunger 85 is in substantially linear relationship to the lateral displacement of the wire.

The frame structure 23 which supports couch roll 7 and slack adjusting roll 9 (Figs. 4 and is provided with a counterbored boss 90 into which is fitted hollow cantilever structure 91 which serves couch roll 7. All the internal parts and arrangements for couch roll 7 are identical with those for breast roll 6 as shown in Fig; 1. The only respect in which the couch roll sub-assembly differs from the breast roll sub-assembly is that the flexible couplings 57 and 59 and the floating shaft 58 are omitted from the couch roll which is free-rotating, driven onl by the Wire 5.

Frame structure 23 (Figs. 4 and 5) is provided with parallel rails 92 adapted to guide the rectangular-shaped flange 93 an integral part of cantilever structure 94 which serves slack-adjusting roll 9. Apart from the rectangular configuration of the inboard-end flange 93 of cantilever structure 94, all internal parts and arrangements of the slack-adjusting roll sub-assembly are identi cal with those of the couch roll sub-assembly.

The flange 93 is held in frictional contact with frame structure 23 by the bolts 95 which pass through elongated holes 96 in the wall of frame structure 23.

In order to effect an adjustment to the amount of slack in the wire 5, bolts 95 are backed off and the slack- .adjusting roll sub-assembly is slid in the desired direction, and by the desired amount, along rails 92, then the bolts 95 are re-tightened. The limit of possible adjustment is set by the length of the elongated holes 96.

a The mounting of the rolls 6, 7, 8 and 9 by the'mounting means described herein makes possible a considerable amount of standardization of component parts such as rolls, shafts, bearings, hollow cantilever structures and bolts. 1

The absence of drilling and suction box in the couch roll not only reduces the cost but removes the source of much operating noise. a

The specific arrangement of the component parts of the Fourdrinier section shown in the present drawings is intended to be illustrative rather than limiting since, 'in practice, various modifications of the illustratedarrangement may be resorted to. For example, the extent to which the couch roll is elevated in relation to the breast roll is variable to give any desired variation of the catenary curvature of the path through which the upper run of the Wire travels from the breast roll to the couch roll. The breast roll and couch roll may also be arranged with their axes in a common horizontal plane or with the breast roll positioned at a higher elevation than the couch roll. The removal of the wet sheet in a vertical direction from the couch roll end of the wire is an important but not an indispensible feature, Also, it would be feasible to direct the formed sheet S in a downward vertical or substantially vertical path from the couch rollend of the wire 5 to and through a high-speed press section 17 positioned below the couch roll. The canting of the wire guide roll 8 in a vertical plane is preferred but not essential since the means provided for canting this guideroll may be arrangedto cant the roll in any other desired direction. These and other modifications are within the scope and spirit of the invention as defined by the appended claims.

I claim:

'1. A high-speed, open-side Fourdrinier machine of relatively narrow width including a vertical frame structure located at the driving side of the machine, a series of relatively short, horizontal roll assemblies including a breast roll assembly, a couch roll assembly and wire return roll assemblies supported solely by said frame structure on the cantilever principle to provide an openside Fourdrinier machine in the sense that, Whether the the machine be at rest or in operation, the whole length of each roll assembly is left free of any supporting means that would interfere with the application and removal of the forming wire, each of said roll assemblies including a hollow cantilever structure having one end secured to and supported by said frame structure, a roll shaft extending through and rotatably supported by said hollow cantilever structure and a roll shell mounted on and fixedly secured to said shaft, a portion of said cantilever structure extending outwardly within said roll shell so as to support said roll shell adjacent the midpoint thereof, an endless Fourdrinier wire trained around said rolls so that, when the Fourdrinier machine is in operation, the upper suspension-carrying run of the wire travels from the breast roll to the couch roll in a curved path free of contact with frictional drag-imparting surfaces and with the concavely curved side of the wire facing upwardly and means for driving said wire at a high rate of speed, said Fourdrinier machine being characterized in that the curvature and speed of travel of the upper run of the wire are predetermined to effect, by centrifugal action, rapid removal of water from a pulp suspension fed onto and carried by the said upper run of the wire. 2. A Fourdrinier section as set forth in claim 1, in which the roll shaft of each roll assembly is rotatably supported by a self-aligning bearing interposed between the shaft and a surrounding wall portion of the hollow cantilever structure through which the shaft extends.

3. A Fourdrinier section as set forth in claim 1, in

which the roll shaft of each roll assembly is rotatably supported by a self-aligning bearing interposed between the shaft and a surrounding wall portion of the hollow cantilever structure through which the shaft extends and in which the shaft is maintained co-axial with the roll shell at the end remote from the frame means by means of a cover plate secured to the outboard ends of the shaft and shell. i 4. A Fourdrinier section as set forth in claim 1, in which the roll shell of each roll assembly is fixedly secured to its supporting shaft by means of an internal diaphragm carried by the shell and provided with a central opening through which the shaft extends, said diaphragm being secured to said shaft'so that the shaft and shell rotate as a unit. i

5; A Fourdrinier section as set forth in claim 1, in which the roll shaft of each of the breast roll and couch roll assemblies is rotatably supported by two self-aligning bearings, one of said bearings being interposed between the shaft and the wall structure of the shaft-carrying hollow cantilever structure at the tending side end of the said cantilever structure and the other of said bearings being housed by the driving side end of said cantilever structure and being adjustably mounted for radial displacement.

6. A Fourdrinier section as set forth in claim 1, including a motor driven shaft connected to the driving side" end of the roll shaft of the breast roll assembly by flexible coupling means.

7. A Fourdrinier section as set forth in claim 1, in which one of the wire return roll assemblies includes a self-aligning bearing interposed between the shaft of said assembly and a surrounding wall portion of the hollow cantilever structure through which the shaft extends, a rockably mounted bearing housing into which the driving side end of the shaft extends, a self-aligning bearing interposed between the shaft and a surrounding portion of said bearing housing and means for rocking said bearing housing.

8. A cantilevered roll assembly as set forth in claim 7 in which the last mentioned means includes a servo-lever having one end rigidly attached to said bearing housing, a spring device acting against the free end of the lever and tending to swing thelever and bearing housing in one direction, a fluid actuated cylinder and piston device acting against the lever and operable to swing the lever and bearing housing in the opposite direction against the resistance of said spring device, and means for routing pressure fluid to and from said cylinder and piston device to control the operation thereof.

9. A cantilevered roll assembly as set forth in claim 7, in which the last mentioned means includes a servo-lever and a restoring-mechanism lever, each having one end rigidly attached to said bearing housing, a spring device acting against the free end of the servo-lever and tending to swing said lever and bearing housing in one direction, a fluid actuated cylinder and piston device also acting against the free end of said servo-lever and operable to swing said servo-lever in the opposite direction against the resistance of said spring device, a valve controlling the routing of pressure fluid to and from said piston and cylinder device, a valve actuator including a valve-actuating plunger, a rocker intermediately pivoted to said plunger, a link connecting one end of said rocker to said valve and a second link connecting the other end of the rocker to said restoring-mechanism lever.

10. A cantilevered roll assembly as set forth in claim 7, in which the said cantilever structure is adjustably secured to the frame structure so that said cantilever structure may be shifted to different positions of horizontal adjustment.

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